The titans’ buying spree has not just minted more than a few 20-something millionaires; it has revolutionized the venture capital business model. Outside of the technology bubble, it used to be that someone struggled for years to build a company before it went public. Sure, some companies were sold when they were at an early stage with little, or even no, revenue, but that strategy reaped tens of millions of dollars, not billions.

The deep pockets and willing buyers among Google and the like have changed the venture capital strategy. Now, the idea is to move into a hot space — social media! — and develop a product that the web conglomerates will buy at prices never before seen in private deals.

The goal is no longer building a business but to be in the orbit of these tech giants. Or to put it another way, to win the lottery. The slowdown in recent months of the I.P.O. pipeline for Internet companies has only made this exit route more important.

You may be asking, so what? This may just be another bubble, and perhaps the bubble is deflating a bit.

Moreover, others, like the indomitable Marc Andreessen, are optimists and deny a bubble exists, citing the low price-to-earnings ratios of the big tech companies and the dearth of good companies to invest in as factors that are driving these prices. Even Mr. Andreessen, though, is critical of the “SF-centric consumer tech party scene.”

You can debate whether there is a bubble or a lasting trend, but there is no doubt about what is driving much of venture capital these days: the headlong rush by Google and other tech giants to become conglomerates.

This is a boon to the cozy, venture capital industry, which has willing buyers that they know well and have lots of cash.

The Internet giants, after all, have core products that mint billions of dollars, if not tens of billions of dollars a year. And that cash needs to go somewhere.

But cash is not the only factor driving the conglomerate wave. Fear is, too. The Internet giants do not want to face obsolescence because of new disruptive technology. So they are riding every hot technology wave. The competition to stay on top has led the tech conglomerates to drive valuations sky high as they battle for start-ups.

Nor do the conglomerates want to lose out to one another. Google, for instance, bought Waze not just because the company offers a potentially good product that Google can link to its own dominant map service, but possibly because its purchase keeps Waze out of the hands of its rival Facebook, which was also a rumored bidder.

New entrants like Alibaba — a Chinese conglomerate seeking to become an American one — are likely to make this competition even more fierce. Alibaba, for example, has spent millions of dollars this year investing in tech companies in the United States.

The Internet giants are not just conglomerates but also the largest venture capitalists on the block. Not only are they buying early-stage businesses to incubate and grow, they are starting their own businesses outside their original mission.

Google is the leader in the conglomerate move, researching blood monitoring for diabetes through contact lenses and investing in 23andMe, the gene analysis company. Google has also developed the product Google Glass for the (hopefully never coming) wearable computing trend. But others like Amazon are in multiple businesses, including cloud computing as well as television and even drones.

In other words, these tech companies keep expanding into new realms, far beyond their core businesses. If you ask them, this is not just a business strategy but grows out of their basic belief that they are incredibly smart and can solve the problems of the world while also delivering products. Not only that, these higher goals justify the incredibly shareholder-unfriendly governance structures of Google and Facebook, which concentrate control with the founders.

The idea that smart people can solve all the world’s problems or at least provide an online friend is a noble one, though, somewhat worthy of an episode of “Silicon Valley,” the satire of the technology culture on HBO.

The paradox is that conglomerates outside the tech sector are an endangered species. The 1960s was the age of the conglomerates. ITT, for example, made both weapons and movies, with the idea that smart managers could operate any business and different operations would diversify the business. But that strategy did not work out as planned. The problem was that managers needed to focus on their businesses. If investors wanted to diversify, they could do so by simply investing in the separate companies. And splitting off businesses would discipline managers not to waste extra cash.

The trend against conglomerates has gotten so intense that hedge funds seek not only to split companies with different business but different types of businesses in the same industries. Darden Restaurants, for instance, has been fighting an activist campaign that it split off Olive Garden and Red Lobster from its higher performing restaurants. Darden responded by first trying to spin off Red Lobster then selling it.

Will that same sensibility eventually catch up to the new web conglomerates? Are they simply management’s larks, with the huge profits of the core businesses allowing the other cash-wasting enterprises? Or is it really true that smart people can do everything and that the conglomerates can replicate the venture capital structure? Perhaps these conglomerates are all about taking control of the web and making sure that no new big competitors spring up.

So far, the success of these purchases is uncertain. Google’s purchase of YouTube, for example, and Facebook’s purchase of Instagram seem to have been nicely timed. But Microsoft’s purchase of Nokia and Google’s acquisition of Motorola Mobile? Maybe not so much. And then, there are the ancient failures, like Yahoo’s purchase of GeoCities and Broadcast.com in 1999. We will see whether the $16 billion for WhatsApp or the money spent developing Google Glass was worth it.

But perhaps the new conglomerates are no better than the old ones. That’s a question consumers and investors — as well as the companies themselves — may want to ask.

The Deal Professor column on Wednesday, about a buying spree that is turning Internet companies into conglomerates, misidentified the cable channel on which the series “Silicon Valley” appears. It is HBO, not Showtime.